A Comparative Study on the Biological Aspects of Shoaling

Abstract

Shoals are unstructured groups of fish that gather together in a social, engaging manner. Various phenotypic and genotypic traits of the shoal mates are known to influence the fishes' choice of shoal. The current study categorized the various elements that affect fish shoaling behavior by analyzing the composition of fish shoals found in natural freshwater habitats. The shoals of fishes near the shallow regions of the water bodies were captured and sorted based on size of the fish shoal and length, weight, colour, sex (studying the stage of maturity of gonads), age (by counting the growth circles formed in the scales) of each individual fish were immediately examined. A randomly selected few fish from the group were kept aside for gut content analysis. Most of the collected samples were homogenous with similar food preferences. The heterogenous groups were also similar in their appearance. Understanding the importance of formation of fish shoals helps in the survival and habitat conservation of the fish species. Many species of fish that act as prey and predators are essential part of the food chain. They also aid in recycling nutrients throughout the ecosystem and managing the numbers of other aquatic organisms. Overfishing of fish shoals can lead to the depletion of total aquatic diversity, which can have significant economic and ecological consequences.